The present invention relates to a pressure rod for a coke discharge apparatus. Heretofore such push rods have been constructed of solid sectional steel.
The solid construction was necessary heretofore in order to make certain that the push rods would be capable to withstand the high temperature difference which may exceed more than 1,000.degree. C. between the coking furnace chamber and the free atmosphere outside of the chamber. The solid sectional components are either welded or riveted to form the frame structure of the prior art push rods. As a result, the weight of such prior art pressure rods may be within the range of between 12 to 24 tons depending on the dimensions of the coking chamber furnace. This heavy type of prior art structure is practically not related at all to the forces that must be taken up by such pressure rods when they are in operation to press out a charge of coke from a coking chamber.
The heavy prior art structures resulted from the fact that it was necessary heretofore to take into account the most disadvantageous load condition which may, for example, occur when the coke has been removed from the chamber but the rod cannot be moved forthwith out of the chamber, for example, due to power failure or to a failure in the drive mechanism of the push rod. For safety reasons it is necessary to take these extreme operating conditions into account and therefore prior art push rods of this type have a large weight resulting from taking into account the maximum adverse operating conditions in order to make sure that a push rod which has to be removed from the coking chamber by means of an emergency drive mechanism or even by hand operated drive means causing a delay in the withdrawal, will not be subject to unacceptable deformations which otherwise could result from the prolonged heat exposure.
However, in spite of the large material expenditure it is not always possible to make sure that prior art pressure rods will remain without structural changes within the material texture of the pressure rod due to excessive heating effects. Further, or in the alternative, it is not possible to assure that prior art rods of this type will not be exposed to a nonuniform cooling which also may result in deformations which could possibly make the further use of the pressure rods at least questionable.